Currently, a hybrid automatic repeat request (HARQ) mechanism is usually used in a Long term Evolution (LTE) system. Specifically, after user equipment (UE) receives downlink data using a physical downlink shared channel (PDSCH), if the UE can correctly receive the downlink data, the UE sends acknowledgment (ACK) information to a base station using a physical uplink control channel (PUCCH); or if the UE cannot correctly receive the downlink data, the UE sends negative acknowledgment (NACK) information to the base station using a PUCCH. When the UE further needs to send, in an uplink subframe in which the UE sends the ACK/NACK information, uplink data, to maintain an uplink single-carrier characteristic of the LTE system and improve efficiency of uplink transmit power, the UE maps the ACK/NACK information and the uplink data to a physical uplink shared channel (PUSCH), and sends both the ACK/NACK information and the uplink data to the base station.
In addition, the LTE system further supports a carrier aggregation (CA) technology. That is, the base station configures at least two carriers for same UE, to improve a data transmission rate of the UE. The at least two carriers include one primary component carrier and at least one secondary component carrier. A PUCCH sending mode in a CA mode includes a channel selection mode and a PUCCH format 3. The channel selection mode supports CA of a maximum of two carriers, and the PUCCH format 3 mode can support CA of five carriers, or can support transmission of a maximum of about 20 ACK/NACK bits. Therefore, when the UE further needs to send, in the uplink subframe in which the UE sends the ACK/NACK information, the uplink data, the PUSCH can carry a maximum of about 20 ACK/NACK bits.
With further evolution of an LTE technology, a PUSCH may need to carry ACK/NACK information of more bits. Therefore, how to enable a PUSCH to carry ACK/NACK information of more bits is a technical problem to be resolved in the present disclosure.